The purpose of this national cohort study is to describe the incidence of work-related injury and musculoskeletal symptoms, identify occupational exposures, and explore risk factors for these outcomes among certified athletic trainers (AT) employed in a variety of industries. This range of industries contributes to a unique combination of occupational exposures to which other heath professions are not exposed. Little is known about the occupational health and risk factors among ATs on a national scale. This project provides an opportunity to develop a better understanding of the hazards faced by ATs so that prevention measures can be identified. We will employ a combination of quantitative and qualitative methods to 1) assemble a 20-year retrospective cohort of ATs, 2) describe the characteristics and calculate rates of work-related injury and illness reported to state workers' compensation over an 8-15 year period, 3) enroll a prospective cohort to determine prevalence and incidence of work-related injury, illness, and musculoskeletal symptoms and document individual management strategies (e.g. self-treatment), and 4) describe and contrast work-related exposures and working conditions in different employment settings by constructing a job exposure matrix. Due to the rise in obesity rates and the promotion of physically active lifestyles in the US, demand for ATs' expertise in care and prevention of activity-related injuries will also increase. Describing work-related exposures and outcomes will be the first step in order to positively impact the health of current and future ATs. The Principal Investigator (PI) will be guided by a team of mentors that includes senior faculty members with extensive experience in surveillance, occupational epidemiology, and exposure assessment, and a senior investigator who is an epidemiologist with expertise in the subject of athletic training. In addition to gaining expertise in the subject of occupational health issues among ATs, the PI will learn to acquire, manage, and analyze large administrative datasets and establish, recruit, and follow a large occupational cohort. This experience will develop the PIs knowledge and skills in survey design, advanced exposure assessment techniques, and comprehensive application of qualitative methods in epidemiologic studies. This project builds upon the PI's prior work experiences and will allow development of new skills while also making a contribution to the study of work- related outcomes among a unique and understudied group of health care providers.